Abstract
OBJECTIVES: Although late-life depression is common, there has previously not been a comprehensive review of chronic depression (CD) in older adults. This systematic review summarizes prevalence rates, potential risk factors, and consequences of CD in later life. METHODS: This preregistered review (PROSPERO: CRD42025649324) searched MEDLINE, Web of Science, CINAHL and PsycINFO from inception to February 2025. Observational studies reporting the prevalence of CD in older adults (mean age 60+) were included. Study quality was assessed using the Joanna Briggs Institutes Critical Appraisal Tool. Random-effects models were used to estimate pooled prevalence across subgroups and meta-regression analyses were used to explore sources of heterogeneity. RESULTS: A total of 39 articles (38 studies) met the inclusion criteria; 20 articles (27 data points) were included in meta-analysis for point prevalence. Overall point prevalence was 4.02% [2.88%-5.35%], with estimates varying by assessment method: 2.30% [1.47%-3.31%] using DSM-IV/DSM-III-R, 7.12% [2.31%-14.22%] using DSM-III/ICD-10% and 5.52% [3.80%-7.54%] using rating scales. Prevalence varied also by region and was higher for women. Consistent risk factors included less physical activity and higher impairment in daily life. Evidence on consequences was sparse. CONCLUSIONS: Approximately 4% of adults aged 60+ meet criteria for CD. Estimates vary substantially by method and region, and potential risk factors and outcomes remain poorly understood. Future studies should target underrepresented subgroups - such as the oldest old, the institutionalized and physically and cognitively impaired individuals-using both dimensional and categorical assessment. CD in late life appears often unrecognized, untreated and underresearched.